Tumor necrosis factor-alpha (TNF-α), a potent cytokine, elicits a broad spectrum of biologic responses, which are mediated by binding to a cell surface receptor. Stauber et al. “Human tumor necrosis factor-alpha receptor: purification by immunoaffinity chromatography and initial characterization” (J. Biol. Chem. 263: 19098-19104, 1988) isolated the receptor for human TNF-alpha from a human histiocytic lymphoma cell line. Hohmann et al. “Two different cell types have different major receptors for human tumor necrosis factor (TNF-alpha)” (J. Biol. Chem. 264: 14927-14934, 1989) concluded that there are 2 different proteins that serve as major receptors for TNF-alpha, one associated with myeloid cells and one associated with epithelial cells.
Using monoclonal antibodies, Brockhaus et al. “Identification of two types of tumor necrosis factor receptors on human cell lines by monoclonal antibodies” (Proc. Nat. Acad. Sci. 87: 3127-3131, 1990) obtained evidence for 2 distinct TNF-binding proteins, both of which bind TNF-alpha and TNF-beta specifically and with high affinity. Gray et al. “Cloning of human tumor necrosis factor (TNF) receptor cDNA and expression of recombinant soluble TNF-binding protein” (Proc. Nat. Acad. Sci. 87: 7380-7384, 1990) isolated the cDNA for one of the receptors. They found that it encodes a protein of 455 amino acids that is divided into an extracellular domain of 171 residues and a cytoplasmic domain of 221 residues. Aggarwal et al. “Characterization of receptors for human tumour necrosis factor and their regulation by gamma-interferon” (Nature 318: 665-667, 1985) showed that tumor necrosis factors alpha and beta initiate their effects on cell function by binding to common cell surface receptors. The TNFA and TNFB receptors have different sizes and are expressed differentially in different cell lines (see Hohmann et al., 1989; and Engelmann et al. “Two tumor necrosis factor-binding proteins purified from human urine: evidence for immunological cross-reactvity with cell surface tumor necrosis factor receptors.” (J. Biol. Chem. 265: 1531-1536, 1990)).
TNF-α-R, referred to by some as TNFR55, is the smaller of the 2 receptors. cDNAs for both receptors have been cloned and their nucleic acid sequence determined (see Loetscher et al. “Molecular cloning and expression of the human 55 kd tumor necrosis factor receptor.” (Cell 61: 351-359, 1990); Nophar et al. “Soluble forms of tumor necrosis factor receptors (TNF-Rs): the cDNA for the type I TNF-R, cloned using amino acid sequence data of its soluble form, encodes both the cell surface and a soluble form of the receptor” (EMBO J. 9: 3269-3278, 1990); Schall et al. “Molecular cloning and expression of a receptor for human tumor necrosis factor.” (Cell 61: 361-370, 1990); Smith et al. “A receptor for tumor necrosis factor defines an unusual family of cellular and viral proteins.” (Science 248: 1019-1023, 1990).
Proteins are known to undergo several degradative pathways, especially deamidation, aggregation, clipping of the peptide backbone an d oxidation. Many of these reactions can be slowed significantly by removal of water from the protein.
However, the development of an aqueous formulation for drug proteins has the advantages of eliminating reconstitution errors, thereby increasing dosing accuracy, as well as simplifying the use of the product clinically, thereby increasing patient compliance. Thus, it is an objective of this invention to provide an aqueous formulation of TNF-binding proteins, which provides acceptable control of degradation products, is stable to vigorous agitation (which induces aggregation), and is resistant to microbial contamination (which allows “multiple use” or “multi-dose” packaging).